AVIONS A PILE A COMBUSTIBLE
?!
Fuel cell-propelled aircraft preparing to fly
New Scientist
12 May 03
The world's first crewed aircraft powered
by fuel cells could be ready for test flights by December 2003.
The experimental one-person craft, being built by
US aerospace company Boeing, will rely entirely on a 25-kilowatt fuel cell
for propulsion once airborne. The fuel cells will provide electrical power
for propeller motors. However, the aircraft will need to use batteries
to accelerate to the required speed during take off.
"If there was ever a way to demonstrate that fuel
cells are safe and usable, this is it," says Judith Agar of Intelligent
Energy, the UK company chosen by Boeing to build the fuel cells. "But it's
essentially a modified glider, so it could glide back to the ground if
the propulsion fails."
Fuel cells use a chemical reaction to generate electricity
from hydrogen and oxygen and the only by-products of the process are heat
and water. The cells are considered a long-term alternative to the internal
combustion engine, which produces greenhouse gases in its exhaust fumes.
Storage problem
A US company, Lynntech, has already built fuel cells
for uncrewed, long duration surveillance aircraft. But Lynntech's Craig
Andrews says it is not feasible to propel anything larger than a light
aircraft using current fuel cell technology.
"The fuel cells are not the problem, it's the hydrogen
storage," he told New Scientist. Providing enough power for a heavier airplane
would require more hydrogen than could feasibly be carried, he says. "Where
primary propulsion is concerned, it's a matter of weight and power efficiency."
However, Boeing does plan to introduce fuel cells
on larger aircraft as a source of auxiliary power for lighting, heating
and in-flight entertainment. Larger airplanes currently use batteries that
are recharged by running the main engines. Agar says the use of fuel cells
could therefore cut the pollution this produces.
A spokesman for Boeing says: "Fuel cells are inherently
cleaner and quieter than auxiliary power units, have fewer moving parts,
and can generate more than twice as much electricity."
Même info par l'AFP, 14 juillet:
Boeing va développer un moteur à hydrogène
pour monomoteur
CHICAGO (Etats-Unis), 14 juil (AFP) - Le constructeur aéronautique
Boeing va développer un moteur électrique fonctionnant à
l'hydrogène capable d'équiper de petits avions monomoteur,
a-t-on appris lundi auprès de la société.
Ce moteur expérimental, qui consiste en une
pile à hydrogène, sera monté sur un planeur à
moteur Katana Xtreme du fabricant autrichien Diamond Aircraft. Une démonstration
en vol est prévue d'ici 2004 ou 2005, précise Boeing.
Ce projet, développé par le centre
de recherches Boeing en Espagne, est mené en collaboration avec
quatre partenaires européens et une société américaine.
A terme, le constructeur aéronautique envisage
de remplacer dans les avions de ligne les unités de puissance auxiliaire
(APU) qui génèrent l'électricité à bord
des avions et fonctionnent grâce à la technologie des turbines
à gaz par ce type de piles à hydrogène.
"Ce projet permettra d'évaluer l'application
potentielle de la technologie des piles à hydrogène, plus
propre, moins bruyante et plus efficace que la technologie actuelle des
turbines à gaz, pour les produits de l'aviation commerciale de l'avenir",
précise Boeing dans un communiqué.
Ceci dit, et s'ils s'avèrent
concluants, les voyageurs devront encore patienter une dizaine d'années
au minimum avant que de tels appareils ne soient mis en service...
